Diversity of root-associated fungi of Rhododendron simsii in subtropical forests: fungal communities with high resistance to anthropogenic disturbances

Species of the Ericaceae or heath family are widely distribute in continental ecosystems and their special ericoid mycorrhizas (ERM) are considered beneficial to their survival and persistence in variable habitats. Currently, increasing anthropogenic disturbances and improper forest management are affecting subtropical forests of China where these native species located. These activities not only affect plant communities above-ground, but also impose pressures on microbial communities below- ground. In this study, root-associated fungal communities of Rhododendron simsii in four forest types under different anthropogenic disturbances were identified using an Illumina Miseq platform, i.e., old growth forests, secondary forests with one cutting (SEC I), secondary forests with two cuttings (SEC II), and Chinese-fir plantations (PLF). Intra- and inter-annual variations were analyzed by comparing samples taken in different seasons and years. The results show that: (1) over 1000 OTUs were found in hair roots with most from the division Ascomycota and Basidiomycota belonging to different functional groups; (2) while there were a few indicator OTUs specific to different forest types, seasons and years, the proportion of shared taxa was quite large, accounting for 44.9–79.4% of the total OTUs; (3) significantly positive correlations were found between disturbance sensitivity and temporal variations in common fungal orders, and both in major fungal orders were significantly different among fungal functional groups in which putative and possible ERM fungi were highly resistant to disturbances and low temporal variations. The high disturbance resistance and temporal persistence of putative ERM fungi may be essential for the successful adaptation of R. simsii in disturbed subtropical forests of China.